..Collectively, the results reveal a tendency for directional evolution toward increased specialization but also indicate that specialization does not always represent an evolutionary dead-end that strongly limits further evolution...

..Replicated shifts in selective regime can demonstrate the primacy of ecological processes in driving evolution and our results illustrate how such shifts are detectable using long-term monitoring of natural populations...

Ecological niche dimensionality and the evolutionary diversification of stick insects

Patrik NosilZoology Department and Centre for Biodiversity Research, University of British Columbia, Vancouver, British Columbia, CanadaPLoS ONE 3:e1907. 2008

..Although further replication of the trends reported here is required, the results suggest that dimensionality of selection may complement genetic and geographic explanations for the degree of diversification in nature...

..cristinae ecotypes is incomplete, and so only the stages before the completion of speciation have been examined. Studies of more divergent taxa within the genus are required to determine the factors that complete speciation...